Method of making piston rings



Nov. 19, 1935. w. WUERFEL 2,021,572

METHOD OF MAKING PISTON) RINGS I Original Filed Feb. 5, 1950 2 Sheets-Sheet 1 'il -III III w. WUERFEL. 'msrnon OF MAKING- PISTON runes Nov. 19, 1935.

Original Filed Feb. 3, "1930 2 Sheets-Sheet 2 Jjel QWMMM Patented Nov. 19, 1935 umreo STATES PATENT OFFICE I 2,021,572 METHOD or MAKING PISTON RINGS William Wuerfel, Philadelphia, Pa., assignor to Wilkcning Manufacturing Company, Philadelphia, Pa., a corporation of Delaware 19 Claims. (01. 29-15652) My invention relates to a new and useful method of making piston rings, particularly piston rings of the so-called sectional type, wherein a plurality (generally two) split annular ring elements are disposed in cooperative relationship to each other within the same ring-receiving groove of a piston; although it is to be understood that the method of the present invention is not limited to the so-called sectional type piston'rings, but is applicable also to the mak ing of piston rings not of the sectional type. My invention relates more paticularly to a method of making piston rings of the sectional type as well as other types of one-piece piston rings, whereby the same may be produced with the greatest facility and economy ofoperation and cost, and whereby a certain uniformity and accuracy in production may be obtained.

One of the objects of my invention is to produce a sectional piston ring having shallow recesses in the juxtaposed faces of the two annular,ring elements, in which any slight variations in the position of the cutting tool will not affect the aggregate overall width of the two juxtaposed recesses in the final product. I

Another object of my present invention is to form any desired shallow recess or channel in one side of any split annular piston ring or piston ring member with the greatest facility and economy of operation, and cost, and with enhancement of the uniformity and accuracy of 7 production. a

mounting two annular and continuous or unbroken ring elements in alignment and in contact with each other along plane parallel and preformed faces thereof, and successively cutting a series of shallow recesses in the juxtaposed and contacting faces of said ring elements by passing a rotating toothed cutter between the two ring members 'so that half-of the cutter 'is'in one ring member, and the other half of the cutter is in the other ring member andthereafter splitting-the ring members-at a point to permit the radial expansion thereof.

The invention further consists in a novel method of making the rings, whereby the. radial slots and annular groove may be inserted or produced in one continuous operation, with the greatest accuracy and facility and whereby said operation may be carried out on a series of rings at one time.

The method of the present invention is not limited, however, to application to rings in their un-split condition orin their unbroken condition, but is equally applicable to the same rings in their split condition or broken condition. Thus, obviously the novel method of the "present invention can be applied to either a pair or a stack of pairs of unsplit or unbroken continuous annular members, and the rings then split after the present method has been completed, or the ring members can be split at one point before the application of the present method thereto, and. then clamped in their collapsed condition or collapsed position for the application of the present method thereto.

For the purpose of illustrating my invention I have shown in the accompanying drawings one form thereof which is at present preferred by me, since the same; has been found in practice to give satisfactory and reliable results, although Referring to the drawings, in which like reference characters indicate like parts v Figure 1 represents a front elevation of a horizontal stack of rings, being subjected to the novel method of the instant invention, with the apparatus shown somewhat diagrammatically.

Figure2 represents a section on line 22 of Figure 1, showing the act of forming the annular grooves.

Figure 3 represents a similar section, showing the act of forming the slots.

Figure 4 represents plan views of a pair of juxtaposed annular members comprising a complete piston ring, as they are removed from the stack shown in Figure 1, upon the completion of the entire method.

pair of juxtaposed annular members constituting a complete ring, shown after the annular members have been split and also showing'said annular member somewhat separated from each vention mounted in a ring groove thereof. This 65 (5 Figure 5 represents a perspective view of a l sectional view is Figure-4. ,1

Figure 7 represents a section on line 1- 1 of Figure 6.

In carrying out the instant invention, ,aseries:

of plane parallel-walled, annular'metnbers are formed of cast iron in any of the usual ways;

. These plane parallel walled, annular members or blanks I, are of a ,width one half that of the entire composite, or multipiece ring, "shown particularly in Figures 5 and 6, as a pair of these narrow, annular members constitute or comprise one ring and more or less fill the width of the ring groove 9 of the piston I ll. The annular mem,- bers may be machined (turned a'nd/or ground) in any known manner to produce the two plane parallel faces thereof.

A stack ll of the plane parallel-walled, annular blanks I is formed upon any suitable axial spindle, arbor, mandrel or the like l2, upon which said stack is firmly clamped by any suitable end plates l3, and nuts H. -The stack 'of clamped, annular blanks I is then mounted on any suitable index head or the like, between centers, so that the stack I l, upon the arbor l2, may be rotated or turned accurately any-given number of angular degrees, corresponding to the positions of the slots. g

A second arbor, spindle or the like 15, having a series of circular saw-like cutters, or milling tools I6 mounted thereon in any convenient or usual manner, as for instance by the spacers l1 and the clamping nuts I8. The circular saws iii are so spaced from each other that their median planes will correspond with, or register with, the contiguous faces of each pair ofblanks I. The cutting arbor 15, having the series of saws l8 mounted thereon, is then rotatably mounted in operativerelationto the stack ll of blanks I, so that the axis of the arbor I5 is parallel with the axis of the arbor l2, and means are provided for driving the arbor-l5.

The particular means or the particular machine tool employed for carrying'out the-instant method" of making piston rings is not here- 'in shown, because any suitable machine tool may.

be employed. Thus, for instance, the instant method may be carried out on any conventional milling machine. gThus, the saw arbor [5 may be attached to the main spindle of a milling machine and supported at its free end l9, upon the center 20 carried by the overhanging arm 2| of the milling machine. In using a conventional milling machine for carrying out the instant-method, a ring arbor l2 may be mounted' upon any conventional index head on the table of the milling machine, directly beneath the saw arbor l5, in'a manner indicated generally in Figure 1. If desired however, any special milling machine may be providedfor carrying out the instant method, so long as it includes a rotary tool arbor, a rotary indexing work support with its axis parallel to the tool axis and with means for successively varying the distance between the tool axis and the work axis, so as to cause the saws to come nearer to the work andto recede,

from the work at intervals to .the desired extent.

It is to be understood that the rotary character of the work support is relative to the tool that the saws It 4 indicated in Figure L k 2,021,372 taken generally on line 66 of' l in fact, givesthe work arbor\ and piston ring blanks relative rotation with respect to the tool In carrying out the novel method of the instant invention, the series of saws I6, rotated at any suitable speed, and the stationary stack of rings H arerbroug t towards each other so 3, -that is, the saws I 6 are fed into the s ack of rings'to a depth sufficient to cut a radial recess of elongated form 22 through each pair of annular members 1; half of the elongated recess being formed in one of the pair-of annular members! and the other half of the recess being formed in the contiguous face of the other of the pair of annular members 1.

The, feeding of the'saws, l6 and the stack of rings I l towards and away from each other may be eifectedeitherby a corresponding lowering and raising of the saw arbor l5, or a corresponding raising and lowering of the,work arbor l2,

or by any other suitable means.

to the stack of rings as After the saws l6 have penetrated the stack of rings to a suitable. depth to cut an elongated r'ecess clear through the rings, the saws are again withdrawn, but not entirely clearof the rings, but

merely are withdrawn to a lesser depth, to wit, a depth corresponding to the depth of the annular groove 23. The stack of rings 'II is then revolved slowly against the rotary saws I6, so that an annular groove of uniform depth and width is cut into the contiguous edge portions of pairs of annular blanks I. The stack of rings H is revolved, until the next slot position is reached, when the rotation of the stackof rings II is stopped and the saws are again fed directly through the stack of rings to out the next-series of elongated slots 22. The saws are then again withdrawn to the depth of the annular groove 23, and the stack of rings ll again rotated slow- 1y against the rotating saws until the next slot position in the rings is reached, when the saws are again fed through the rings while the rings are stationary, This successive series of steps is repeated until the entire series of slots 22 is cut through the stack of rings and the entire annular groove 23 completed around the rings.

The number of slots 22 provided in the rings is optional and may be varied, depending on several factors, among them, the diameter 0.? the rings. In the particular illustration shown in Figures 3 and 4, five slots 22 are provided in the entire ring. Thus, the, rings are fed around to stationary positions approximately 72 apart. If desired,rthe intermittent rotary feeding motion K of the rings may be effected by any suitable automatic means.

' The result of the foregoing method will be pairs of annular members I, shown particularly in Figures 4 and 5, having elongated recesses 22 in the contains an annular groove 23 in the outer periphery of the ring. If no outer annular groove is desired, the cutter is entirely withdrawn after eachradial cut.

The annular members I may then be split as an outward radial direction, by an outward tension set into the ring by any suitable means, or

- at 24, so as to permit of the outward radial expension thereof. If desired, the rings may be caused to bear against the cylinder wall 25, in

they may be forced outwardly with a uniform radial pressure, by any suitable spring expander 26 inserted in the ring groove behind the piston ring, of any suitable type or construction, as for instance that shown in my Patent No. 1,707,035.

The method of the present invention may be I applied to rings that are first split (according to any ofv the -cast-out-of-round methods, or

time.

, By means of the novel method herein described; a composite or multipiece piston ring of this character, to wit, including an annular oil groove and a series of radial elongated slots, may be produced with the greatest facility and accuracy and with the minimum labor and cost.

By reasonof the fact that the same cutting operationproduces the recess in the juxtaposed faces of both'ring members of the piston ring, any slight displacement of the cutter towards one or the other of the ring elements during the cutagainst the cylinder walls. resultant or, effective sealingaction ting operation will not alter the aggregate overall width of the two juxtaposed recesses.

The composite or multipiece piston ring 8, formed by the instant novel method, is possessed of certain advantages. Thus, the composite ring 8 is provided with a pair of comparatively narrow, annular'bearing surfaces 27, which contact with the cylinder wall 25, and an annular groove 23, intermediate -said similar bearing surfaces 27!. The effect of the construction is to gather oil into the annular groove 23. The oil collected in the groove 23 then enters the elongated slotsor re cesses 22 intermediate the two parts '7 of the ring 8, and passes behind the ring into the ring groove 9. If desired, a series of drain holes may be provided in the bottom of the ring groove 9 through the wall of the piston l0, into the interior of the piston and the oil thus gathered in the groove 23 may be drained back into the crank case, in this manner. If desired, however, the composite or multipiece piston ring 8 of the instant novel construction, may be used in piston ring grooves without any oil drain holes. 7

When the piston ring 8 of this construction is thus used without any oil drain holes, the oil gathered or scraped into the annular groove 23 on the successive reciprocations of the piston I0, is forced into the elongated slots or recesses 22,

and also into the space in the ring groove behindthe ring, and since the oil cannot escape from said spaces, 'it has a tendency to exert a hydraulic pressure upon the two halves ormembers l of the ring 8, in opposite directions, tending to force them against the corresponding side walls 28 of This hydraulic pressure of .wardly in a. radial direction. By this means the confined oil has a tendency, by reason of the hydraulic pressure thereof, to force the two halves of the ring apart and thus to firmly fill the ring groove, I and also to force the ring outwardly In this manner, the of the ring is enhanced. L

While the methodof the present invention is herein illustrated with particular reference to two-piece or "sectional oil control rings or compression rings of the slotted type, it will be understood that the present method is capable of producing other forms of rings for other purposes, including one-piece rings for oil control purposes, and also for compression purposes, and the method of the present invention may be used whenever a partial or interrupted outer peripheral corner channel is to be formed, on ring members or split annular piston rings, .or whenever slots are desired in one side of annular ring members or split annular piston rings.

,I am aware that my invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

. Having thus described my invention, what I hereby claim .as new and desire to secure by Letters Patent, is:

1. The method of making sectional piston rings which consists in clamping together a pair of plane-parallel faced annular members in abutting relation to each other, and forming a series of circumferentiallyspaced shallow recesses in the juxtaposed and abutting faces of each of said pair of annularmembers by repeatedly causing a rotating saw-like cutter to penetrate through said pair of annular members in a generally radial direction at circumferentially spaced points with the axis of rotation of said cutter sub-' stantially parallel with the axis of said ring members,'and with the thickness of the cutter divided generally equally between the two ring members.

2. The method of making sectional piston rings which consists in clamping together a pair of plane p'arallel faced annular members in abutting relation to each other, and forming a series of circumferentially spaced shallow recesses in the juxtaposed and abutting faces of each of said pair of annular members by repeatedly causing a rotating saw-like cutter to penetrate through said pair of annular members in a generally radial direction at circumferentially spaced points with the axis of rotation of said cutter substantially parallel with the axis of said ring members, and with the thickness of the cutter divided generally equally between the two ring members, and thereafter splitting the ring members at a suitable point to break the continuity thereof.

parallel. faced annular members in abutting relation to each other, and forming an outer annular recess in the adjacent outer peripheral corners of'said annular members, and a series of shallow recesses in the juxtaposed faces thereof, by rotating said pair of clamped annular members against the periphery of a rotary cutter and causing said cutter repeatedly to penetrate through said pair of annular members in a generally radial "direction at circumferentially spaced points, with the axis of rotation of said cutter substantially parallel with the axis of said ring members and with the thickness of the cutter divided generally equally between the two ring members.

4. The method of making piston rings which consists in clamping together a pair of planeparallel faced annular members in abutting relation to each other, and forming an outer annular points, with the axis of rotation of said cutter substantially parallel with; the axis of said ring members and with the thickness ofthe cutter divided generally equally between the -two ring members, and thereafter splitting the ring anembers at a point irr their circumference to break the continuity thereof.

5. The method of making a piston ring which consists iniclamping'togethen a pair of )planeparallel faced annular members in abutting relation to each other, forming an annular groove in the outer periphery thereof, -divided between said pair of annular members, and forming a series of elongated slots extending radially through saidpair of annular members in con tinuation of said'annular groove, by causing said pair of clamped annular members to be fed cir cularly and generally radially with respect to a rotating saw-like \cutter, the axis of ,which is parallel with the axis of the pair of clamped annular members. g

consists in clamping a stack of aligned and abutting annular members upon any suitable means,

a pair of said annular .membershavingan aggregate widthequal to the width of the desired 85 piston ring, providing a series of similar and spaced and rotary cutting tools upon a common 'axis generally parallelsto the axisof, said stack of rings, said rotary cutting tool being in alignment with and infoperative juxtaposition to the 16 contiguous faces of each pair of said' annular members in said stackff eedingsaid stack of rings against said series, of rotary cuttingtools, to

form cbrr'espondmg annular grooves in said stack of annular members, and feeding: said stackof annularimembers' and said rotary cutting tools radially relativeto each'oth'er, to forman elongated slot extending through each pair of said annular members in a radial direction.

7. A method of makingpiston rings which consists in clamping together a pair of plane parallel faced annular rings in abutting relation to each other, and forming an outer annular recess n the adjacent outerperipheral corners of said annular rings, by rotating said pair of annular rings against a vrotating saw-like cutter, with the axis of rotation ofsaid cutter substantially parallel with the axis of said ring members and with the thicknessof the cutter divided generally equally between the two ring members.

consists in clamping tog-ether'a pair of plane parallel faced annular rings in abutting'relation to each other, rotating said pair of clamped annular rings against the periphery of a rotating 65 saw-like cutter so asto form an outer annular I recess'in the adjacent outer peripheral corners of said -annular ring members, said annular recess extending substantially the complete circumference of said. annular rings, with the axis 70 of rotation of said cutter substantially parallel with the axis of said ring members.

\ 9. The method ofmaking piston rings which consists in clamping together a pair of plane parallel faced annular rings in abutting relation to 15 each othenand forming 5 series of circumferen- 6, The method of making piston rings which.

8. The method of making piston rings which vtially spaced shallow recesses in the juxtaposed and. abutting faces of each of said pair of annular rings by repeatedly causing a rotating sawlike cutter to penetrate said pair of annular rings to predetermined depth and rotating said 5 pair of annular rings with respect to said cutter,

the axis of rotation of said cutter being substantially parallel with the axis of said ring members and with the thickness of the cutter divided generally equally between the two ring members.

10'. 'Ifhe method of making piston rings which consists in clamping together a pair of plane,

parallel-faced annular members in abutting relation to each other upon a rotatable member, disposing a rotating saw-like cutter in juxtaposition to said pair of clamped annular mend ers upon an axis parallelto the axis of saidannular members andwith thev axial width of the sawlike cutter divided generally equally between the pair of clamped annular members, rotating said 20 pair of clamped annular members against the periphery of said rotating saw-like cutter to form "an, outer annular recess in the adjacent outer peripheral'comers of said annular members, and successively and oppositely varying the distance 25 between the axis of said annular members and said saw-like cutter in, less than one complete revolution of said" pair of clamped annular members in relation to the rotating saw-like cutter. 1l.- The-method of making sectional piston 30 rings whic h consists in clamping together a mum;- ber of. pairs of plane-parallel faced annular members in'abutting relation to each other, and forming a series of circumferentially spaced;

shallow recesses in the juxtapo:ed andv abutting 35 faces of each annular member of each of said pairs of annuiarmernbers by repeatedly causing acorresponding number of rotating saw-like cutters to penetrate through said pairs of an- .nularmembers in a generally radial direction igo at circumferentially spaced, points with the axis of rotation of said cutters substantially parallel with the axis of said ring members, and with the thickness pf each cutter divided generally equally between a pair of ring members. x

.2. The method of making sectional piston rings which consists in clamping together a num- .ber of pairs of plane-parallel faced annular members in abutting relation to each' other, and forming a series of circumferentially spaced 50 shallow recesses in the juxtaposed and abutting a with the axis of said ring members, and with the thickness of each cutter divided generally equally between a pair of ring members, and, thereafter splitting the ring members at a suitable point to break the continuity thereof. I p 13. The method of making piston rings which,

consists in clamping together a number of pairs of plane-parallel faced annular members in abutting relation to' each other, and forming an outer annular recessin the adjacent outer peripheral corners of pairs of said annular mem-' bers, and a series ,of shallow recesses in the juxtaposed faces of pairs of said annular members, by rotating said pairs of clamped annular members against'the periphery of a correspondingnumber of rotary cutters and causing corresponding number of cutters repeatedly to penetrate through said pairs of annular members in a generally radial direction at circumferentially spaced points, with the axis of rotation of said cutters substantially parallel with the axis of said ring members and with the thickness of each cutter divided generally equally'between a pair of ring members.

14. The method of makingpiston rings which consists in clamping together a number of pairs of plane-parallel faced annular members in abutting relation to each other, and. forming an outer annular recess in the adjacent outer peripheral corners of said annular members, and a series of shallow recesses in the juxtaposed faces thereof, by rotating said pairs of clamped annular members against the periphery of a corresponding number of rotary cutters and causing said corresponding number of cutters repeatedly to penetrate through said pairs of annular members in a generally radial direction at circumferentially spaced points, with the axis of rotation of said cutters substantially parallel with the axis of said pairs of ring members and with the thickness of each cutter divided generally equally between a pair of ring members, and thereafter splitting the ring members at a point in their circumference to break the continuity thereof. 7

15. The method of making piston rings which consists in clamping together a number of pairs of plane-parallel faced annular members in abutting relation to each other, forming annular grooves in the outer peripheries thereof, divided between the two members of said pairs of annular members, and forming a series of elongated slots extending radially through said pairs of annular members in continuation of said annular grooves, by causing said pairs of clamped annular members to be fed circularly and generally radially with respect to a corresponding number of rotating saw-like cutters, the axes of which are parallel with the axes of the pairs of clamped annular members.

16. A method of making piston rings which consists in clamping together a number of pairs of plane parallel faced annular rings in abutting relation to each otherfiand forming an outer annular recess in the adjacent outer peripheral corners of said annular rings, by rotating said pairs of annular rings against a corresponding number of rotating saw-like cutters, with the axis of rotation of said cutters substantially parallel with the axis of said ring members, and with the thickness of each cutter divided generally equally between a pair of ring members.

17. The method of making piston rings which consists in clamping together a, number of pairs of plane parallel faced annular rings in abutting 5 relation to each other, rotating said pairs of 'clamped annular rings against the periphery of a corresponding number of rotating saw-like cut-' ters so as to form an outer annular recess in the adjacent outer peripheral corners of said annu- 1 lar ring members, said annular recess extending substantially the complete circumference of said annular rings, with the axis of rotation of each cutter substantially parallel with the axis of said ring members. 15

18. The method of making piston rings which consists in clamping together a number of pairs of plane parallel faced annular rings in abutting relation to each other, and forming'a series of circumferentially spaced shallow recesses in 0 the juxtaposed and abutting faces of each annular member of each of said pairs of annular rings by repeatedly causing a corresponding number of rotating saw-like cutters to penetrate said pairs of annular rings to predetermined depth and rotating said pairs of annular rings with respect to said cutters, the axis of rotation of each cutter being substantially parallel with the axis of said ring members, and with the thickness of each cutter divided generally equally between a pair of ring members.

19. The method of making piston rings which consists in clamping together a number of pairs of plane, parallel-faced annular members in abutting relation to each other upon a rotatable 5 member, disposing a corresponding number of r0 tating saw-like cutters in juxtaposition to said pairs of clamped annular members upon an axis parallel to the axis of said annular members and with the axial width of one of the saw-like cutters divided generally equally between the two annular members of each pair of said annular members, rotating said pairs of clamped annular members against the peripheries of said rotating saw-like cutters to form outer annular recesses in the adjacent outer peripheral corners of said pairs of annular members, and successively and oppositely varying the distance between the axis of said annular members and said saw-like cutters in less than one complete revolution of said pairs of clamped annular members in relation to the rotating saw-like cutters.

WUERFEL. 

